Datasheet

LT3756/LT3756-1/LT3756-2
3
375612fb
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 24V, SHDN/UVLO = 24V, CTRL = 2V, PWM = 5V, unless otherwise
noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Minimum Operating Voltage V
IN
Tied to INTV
CC
l
6 V
V
IN
Shutdown I
Q
SHDN/UVLO = 0V, PWM = 0V
SHDN/UVLO = 1.15V, PWM = 0V
0.1 1
5
µA
µA
V
IN
Operating I
Q
(Not Switching) PWM = 0V 1.4 1.7 mA
V
REF
Voltage 100µA ≤ I
VREF
≤ 0µA
l
1.965 2.00 2.045 V
V
REF
Line Regulation 6V ≤ V
IN
≤ 100V 0.006 %/V
SENSE Current Limit Threshold
l
98 108 118 mV
SENSE Input Bias Current Current Out of Pin 40 µA
SS Pull-Up Current Current Out of Pin 8 10 13 µA
Error Amplifier
ISP/ISN Full-Scale Current Sense Threshold FB = 0V, ISP = 48V
l
96 100 103 mV
ISP/ISN Current Sense Threshold at CTRL = 0V CTRL = 0V, FB = 0V, ISP = 48V –12 –9.5 –7 mV
CTRL Pin Range for Current Sense Threshold Adjustment
l
0 1.1 V
CTRL Input Bias Current Current Out of Pin 50 100 nA
LED Current Sense Amplifier Input Common Mode Range (V
ISN
)
l
2.9 100 V
ISP/ISN Short-Circuit Threshold ISN = 0V 115 150 200 mV
ISP/ISN Short-Circuit Fault Sensing Common Mode Range (V
ISN
)
l
0 3 V
ISP/ISN Input Bias Current (Combined) PWM = 5V (Active), ISP = ISN = 48V
PWM = 0V (Standby), ISP = ISN = 48V
55
0 0.1
µA
µA
LED Current Sense Amplifier g
m
V
(ISP – ISN)
= 100mV 120 µS
VC Output Impedance 1V < VC < 2V 15000 kΩ
VC Standby Input Bias Current PWM = 0V –20 20 nA
FB Regulation Voltage (V
FB
)
ISP = ISN
l
1.220
1.232
1.250
1.250
1.270
1.265
V
V
FB Amplifier g
m
FB = V
FB
, ISP = ISN 480 µS
FB Pin Input Bias Current Current Out of Pin 40 100 nA
FB Open LED Threshold OPENLED Falling
(LT3756 and LT3756-2)
V
FB
–
65mV
V
FB
–
50mV
V
FB
–
40mV
V
FB Overvoltage Threshold PWMOUT Falling V
FB
+
50mV
V
FB
+
60mV
V
FB
+
75mV
V
VC Current Mode Gain – (∆V
VC
/∆V
SENSE
)
4 V/V
Oscillator
Switching Frequency R
T
= 100k
R
T
= 10k
l
90
925
100
1000
125
1050
kHz
kHz
Minimum Off-Time 170 ns
Linear Regulator
INTV
CC
Regulation Voltage 7 7.15 7.3 V
Dropout (V
IN
– INTV
CC
) I
INTVCC
= –10mA, V
IN
= 7V 1 V
INTV
CC
Undervoltage Lockout 3.9 4.1 4.3 V
INTV
CC
Current Limit 14 17 23 mA
INTV
CC
Current in Shutdown SHDN/UVLO = 0V, INTV
CC
= 7V 8 12 µA